Technical Field
The present invention relates to regenerative control technology for a motor.
Background Art
Electric power-assisted vehicles, such as electric bicycles driven by battery power, use sensors provided on brake levers. These sensors respond to the usage of the brakes by the rider in order to enable regenerative operation of the motor, which stores the kinetic energy of the vehicle into the battery and improves the travel distance of the vehicle.
Bicycles, unlike automobiles and motorcycles, do not have engine brakes, resulting in a sense of danger for the rider when descending long downward slopes at a high speed. Therefore, the speed must be controlled through operation of the brakes. There are problems, however, such as this kind of braking operation being bothersome for the rider, and hand fatigue occurring due to prolonged operation of the brakes.
Meanwhile, it is possible to control regenerative braking through operation of the brakes, but difficult to provide intended regenerative braking force by the rider due to the operation of the brakes being troublesome and due to ordinary brake operation detection devices only being able to detect two states: a state in which the brakes are being operated and a state in which the brakes are not being operated.
There is conventional technology that detects analog braking operation signals in accordance with the tension of the brake wire and brake lever, and then controls the regenerative braking force in accordance with this. There are problems, however, such as the brake wire stretching due to passage of time, mismatch between the operating point of the mechanical brakes and the braking operation amount controlling the regenerative braking force, and the mechanical brakes operating before efficient regenerative braking has occurred, thereby wasting the kinetic energy as heat.
There is also technology that automatically performs regenerative braking according to pre-determined configurations in electric power-assisted vehicles such as in electric bicycles; however, these pre-determined configurations do not necessarily coincide with the intentions of the rider. In other words, the speed at which a rider feels comfortable going down a long slope varies depending on road width, weather conditions, the physical condition of the rider, and the like, for example. Accordingly, depending on the rider, there may be a deceleration that is excessive enough to cause panic, or conversely an insufficient deceleration that causes the rider to feel a sense of danger.